Evaluation of Xpert MTB/RIF for Detection of Tuberculosis from Blood Samples of HIV-Infected Adults Confirms Mycobacterium tuberculosis Bacteremia as an Indicator of Poor Prognosis

Feasey, Nicholas A.; Banada, Padmapriya P.; Howson, William; Sloan, Derek J.; Mdolo, Aaron; Boehme, Catharina; Chipungu, Geoffrey; Allain, Theresa J.; Heyderman, Robert S.; Corbett, Elizabeth L.; Alland, David

doi:10.1128/jcm.00330-13

Cited by 51 publications

(51 citation statements)

References 19 publications

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“…However, many of these prior studies were poorly controlled, and the specificity of the assay used was often uncertain. A recent study showed that the Xpert assay detected TB in blood samples from HIV-positive patients with a sensitivity approximately equal to the sensitivity of blood culture (40). However, we found that only 8.3% of the HIV-negative subjects in our study were TB positive upon blood testing.…”

Section: Figcontrasting

confidence: 55%

Exploring Alternative Biomaterials for Diagnosis of Pulmonary Tuberculosis in HIV-Negative Patients by Use of the GeneXpert MTB/RIF Assay

et al. 2013

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The utility of the GeneXpert MTB/RIF (Xpert) assay for detection of Mycobacterium tuberculosis in sputum samples has been extensively studied. However, the performance of the Xpert assay as applied to other readily accessible body fluids such as exhaled breath condensate (EBC), saliva, urine, and blood has not been established. We used the Xpert assay to test EBC, saliva, urine, and blood samples from HIV-negative, smear-and culture-positive pulmonary tuberculosis (TB) patients for the presence of M. tuberculosis. To compare the ability of the assay to perform bacterial load measurements on sputum samples with versus without sample processing, the assay was also performed on paired direct and processed sputum samples from each patient. The Xpert assay detected M. tuberculosis in none of the 26 EBC samples (sensitivity, 0.0%; 95% confidence interval [95% CI], 0.0%, 12.9%), 10 of the 26 saliva samples (sensitivity, 38.5%; 95% CI, 22.4%, 57.5%), 1 of 26 urine samples (sensitivity, 3.8%; 95% CI, 0.7%, 18.9%), and 2 of 24 blood samples (sensitivity, 8.3%; 95% CI, 2.3%, 25.8%). For bacterial load measurements in the different types of sputum samples, the cycle thresholds of the two M. tuberculosis-positive sputum types were well correlated (Spearman correlation of 0.834). This study demonstrates that the Xpert assay should not be routinely used to detect M. tuberculosis in EBC, saliva, urine, or blood samples from HIV-negative patients suspected of having pulmonary tuberculosis. As a test of bacterial load, the assay produced similar results when used to test direct versus processed sputum samples. Sputum remains the optimal sample type for diagnosing pulmonary tuberculosis in HIV-negative patients with the Xpert assay.

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Section: Figcontrasting

confidence: 55%

Exploring Alternative Biomaterials for Diagnosis of Pulmonary Tuberculosis in HIV-Negative Patients by Use of the GeneXpert MTB/RIF Assay

et al. 2013

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“…The frequency of various factors contributing to test failures is described in Table 2. Literature studies 7,11 suggest that the leading cause of GeneXpert MTB/RIF assay failure results observed in the present study was due to inadequate sample processing and equipment malfunction. Like any other automated laboratory technology, GeneXpert MTB/RIF assay also require a stable electric power supply, and even a short-term interruption of power would result in test failures.…”

Section: Discussionmentioning

confidence: 80%

Utility of GeneXpert Mycobacterium tuberculosis/Rifampin Assay for Extrapulmonary Tuberculosis Samples

Shetye¹,

Yadav²,

Chheda³

et al. 2017

MGM Journal of Medical Sciences

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A total of 3,806 samples from suspected cases of extrapulmonary tuberculosis (EPTB) were subjected to GeneXpert Mycobacterium tuberculosis (MTB)/rifampin (RIF) assay. Samples consisted of body fluids, pleural fluids, pus and aspirates, lymph node (LN) tissues, and others. Mycobacterium tuberculosis positivity was detected in 18.10% and RIF positivity in 2.73% samples. The MTB/RIF positivity was found highest in pus and aspirates (40.38%). In this study, assay failure rate for GeneXpert MTB/RIF assay was very low (1.99%). It is concluded from this study that GeneXpert MTB/RIF is an efficient, reliable, simple, and fast technique for rapid diagnosis of EPTB in our country where incidence of tuberculosis remains high.

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“…Furthermore, the programmable fluidics of the assay cartridge enabled us to perform double nested-PCR amplification, substantially improving assay sensitivity. The Xpert system has been used successfully to detect Mycobacterium tuberculosis and Staphylococcus aureus directly from clinical blood samples (25,31,32). The current study demonstrates that in the case of F. tularensis bloodstream infection, our approach can diagnose bacteremia several days earlier than conventional PCR or blood culture, with the first cases diagnosed at the time of first symptom development.…”

Section: Discussionmentioning

confidence: 81%

Sensitive Detection of Francisella tularensis Directly from Whole Blood by Use of the GeneXpert System

et al. 2017

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Francisella tularensis is a potential bioterrorism agent that is highly infectious at very low doses. Diagnosis of tularemia by blood culture and nucleic acidbased diagnostic tests is insufficiently sensitive. Here, we demonstrate a highly sensitive F. tularensis assay that incorporates sample processing and detection into a single cartridge suitable for point-of-care detection. The assay limit of detection (LOD) and dynamic range were determined in a filter-based cartridge run on the GeneXpert system. F. tularensis DNA in buffer or CFU of F. tularensis was spiked into human or macaque blood. To simulate detection in human disease, the assay was tested on blood drawn from macaques infected with F. tularensis Schu S4 at daily intervals. Assay detection was compared to that with a conventional quantitative PCR (qPCR) assay and blood culture. The assay LOD was 0.1 genome equivalents (GE) per reaction and 10 CFU/ml F. tularensis in both human and macaque blood. In infected macaques, the assay detected F. tularensis on days 1 to 4 postinfection in 21%, 17%, 60%, and 83% of macaques, respectively, compared to conventional qPCR positivity rates of 0%, 0%, 30%, and 100% and CFU detection of blood culture at 0%, 0%, 0%, and 10% positive, respectively. Assay specificity was 100%. The new cartridge-based assay can rapidly detect F. tularensis in bloodstream infections directly in whole blood at the early stages of infection with a sensitivity that is superior to that of other methods. The simplicity of the automated testing procedures may make this test suitable for rapid point-of-care detection.

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Evaluation of Xpert MTB/RIF for Detection of Tuberculosis from Blood Samples of HIV-Infected Adults Confirms Mycobacterium tuberculosis Bacteremia as an Indicator of Poor Prognosis

Cited by 51 publications

References 19 publications

Exploring Alternative Biomaterials for Diagnosis of Pulmonary Tuberculosis in HIV-Negative Patients by Use of the GeneXpert MTB/RIF Assay

Exploring Alternative Biomaterials for Diagnosis of Pulmonary Tuberculosis in HIV-Negative Patients by Use of the GeneXpert MTB/RIF Assay

Utility of GeneXpert Mycobacterium tuberculosis/Rifampin Assay for Extrapulmonary Tuberculosis Samples

Sensitive Detection of Francisella tularensis Directly from Whole Blood by Use of the GeneXpert System

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